Resistors are standard components in many semiconductor integrated circuits. For example, the resistor is typically used to control respective resistances of other electronic components of an integrated circuit, which can be a radio frequency (RF) circuit (e.g., an oscillator, phase-shift network, filter, converter, etc.), a memory (e.g., a dynamic random access memory (DRAM), a static random access memory (SRAM), etc.) circuit, and any of a variety of analog/mixed-signal circuits.
The resistor is typically implemented by a thin film resistor, formed of a metal thin film, so as to provide a low temperature coefficient of resistivity (TCR) and a wider sheet resistance tolerance when compared to resistors formed in other structures, and/or of other materials. Conventionally, when making such a thin film resistor concurrently with a metal gate of a field-effect transistor, which is typically referred to as a middle-end-of-line (MEOL) process, a chemical-mechanical polishing (CMP) process is performed on a substantially long polysilicon line structure that overlays the metal thin film to form the metal gate and contacts of the thin film resistor. Due to such substantially long extension of the polysilicon line structure, a CMP dishing and/or erosion effect occurs to the polysilicon line structure, which may directly or indirectly cause various issues such as, for example, over-polishing on the polysilicon line structure, over-etching on respective contact of the thin film resistor, etc.
Therefore, conventional thin film resistor, and methods to form the same are not entirely satisfactory.